How Heat Loads Are Calculated

Here is a subject that is going to make your day. It’s so exciting that you’re going to call someone right away to share this new bit of knowledge I’m about to share with you. Okay, maybe not… It’s actually quite boring. But, this task is important enough for me to feel that it’s worth writing about. So, what exactly is this heat load calculation and what sort of function does it serve?

A heat load calculation is exactly what the name implies. It determines the amount of heat that is inside your home and needs to be removed by your air conditioner. Usually, this test is performed when you are planning to install a new air conditioner. Its purpose is to determine the proper size of an air conditioning system that will suit your home. You might wonder why not just install the same sized system that was in there before, but that is not a good idea.

When a technician is sizing your home for a new comfort system, he has many parameters to consider. When we do heat load calculations, we find that time and time again systems in many homes are oversized. This is because of the old thought that bigger means better, but in the a/c business if you don’t pay attention to what you actually need in a comfort system, you’re asking for trouble.

Your home comfort system serves two major functions: to reduce temperature and reduce humidity. As I’ve discussed in my recent articles, proper humidity reduction is achieved when air passes through your a/c system a predetermined number of times per hour. If a system is too large it will bring the temperature down too quickly, lowering the number of air exchanges and will fail to properly dehumidify your home. If a system is oversized and isn’t dehumidifying properly, it will provide an excellent environment for microorganisms to grow.

So, after this long explanation you may ask, “Why do I need to know about heat load calculation?” My answer is that you don’t have to know how to do it, but you should know what it is. Next time you are shopping for a new system, you can make sure that your air conditioning contractor knows how to properly assess what type of system your home will need.

As always, thanks for reading,

Bryan
Bryan Hayes, along with his brother Todd, is a co-owner of a Sanibel Air Conditioning company on Sanibel, FL. They also own and operate an island-based electrical service company Sanctuary Island Electric, Inc. Bryan can be reached at Bryan@Sanibelair.com